The spool on a Snap N' Go Weed Eater lawn trimmer houses the cutting line used to trim those weeds. This plastic spool can be removed to refill the cutting line or to replace a broken spool. Often, if you tapped too hard to get out more line you can crack the spool or bend it so it no longer spins inside the head. You need to replace these spools as soon as they show signs of damage to keep the rest of the trimmer working correctly.
Move the starting button into the "STOP" position. Disconnect the power source by unplugging the electrical cord, removing the battery or unhooking the rubber boot from the spark plug, according to your Snap N' Go's engine type.
Set the butt of the Weed Eater's engine onto the ground. Hoist the trimmer shaft into the air. Cradle your arm around the shaft and hold the moving part of the head steady. Pull the center tap button firmly to release the head's cap.
Take the cap off and slide the spool out of the cutting head. Leave the spring connected to the cutting head. Remove any old line from the spool. Check the spool for cracks and other damage. Replace the spool if necessary.
Thread the new spool's trimmer lines into the eyelets on the cutting head. Push the new spool against the center hub and spring until it snaps into place. Refit the cap to the spool.